import numpy as np
import matplotlib.pyplot as plt

def sigmoid(x):
    return 1/(1+np.exp(-x))

if __name__ == '__main__':
    X = np.arange(-5.0,5.0,0.1)
    Y = sigmoid(X)

    plt.plot(X,Y)
    plt.ylim(-0.1,1.1)

    plt.show()